On August 19, 2026, a divided panel of the U.S. Court of Appeals for the Ninth Circuit held in Ding v. Structure Therapeutics, Inc., No. 25-1532, that a former employee who discovered during arbitration that her alleged workplace mistreatment may have been based on sex could invoke the Ending Forced Arbitration of Sexual Assault and Sexual Harassment Act of 2021 (the “EFAA”) to end the arbitration and pursue her entire case in court. The panel also held that a sex-based hostile work environment claim under California’s Fair Employment and Housing Act may qualify as a “sexual harassment dispute” under the EFAA even if the alleged harassment was not sexual in nature.
Enacted in 2022, the EFAA amended the Federal Arbitration Act to provide that, at the election of a person alleging conduct constituting a sexual harassment or sexual assault dispute, a predispute arbitration agreement is invalid and unenforceable “with respect to a case” that relates to the covered dispute. The EFAA defines a “sexual harassment dispute” by reference to applicable federal, tribal, or state law.
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Structure Therapeutics USA, Inc. (“Structure”) hired Dr. Ding Ding as its Chief Financial Officer in December 2021, and her offer of employment required all employment disputes to be resolved through arbitration. Before she was hired, Structure’s Chief Executive Officer circulated an email describing his “ideal phenotype” for the position and identifying two men as examples. According to Dr. Ding’s complaint, the CEO subsequently sidelined her and limited her responsibilities. The CEO later testified that he took into account complaints by several male Wall Street bankers that she was “difficult to work with” and “lecture[d]” them when recommending her termination.
In October 2022, Dr. Ding initiated arbitration, asserting discrimination, retaliation, and harassment claims based on national origin and her status as a victim of domestic violence. During discovery, she obtained the “ideal phenotype” email and other evidence that, she alleged, showed that her workplace mistreatment was based on sex. After more than a year in arbitration, Dr. Ding withdrew based on Structure’s allegedly late payment of arbitration fees and filed suit in California state court, adding sex discrimination and sex-based hostile work environment claims. Structure removed the action to federal court and moved to compel arbitration. The district court denied the motion, and the Ninth Circuit affirmed.
The Ninth Circuit rejected Structure’s argument that initiating arbitration categorically barred Dr. Ding from later electing to proceed in court under the EFAA. The majority explained that the statute does not limit when a plaintiff may allege a covered claim or provide that filing other claims in arbitration extinguishes EFAA rights. When Dr. Ding initiated arbitration, she was not alleging a sexual harassment dispute and, according to the district court’s factual findings, did not yet know that her alleged mistreatment was based on sex. She therefore made only one election under the EFAA: to pursue the newly discovered sexual harassment claim in court.
The majority emphasized that ordinary waiver principles continue to apply. A plaintiff may waive EFAA rights if the plaintiff is aware of the facts giving rise to a sexual harassment claim and either unduly delays bringing the claim through intentional acts or chooses to pursue the claim in arbitration. But the district court found no evidence that Dr. Ding knew she had a plausible sexual harassment claim when she initiated arbitration, and the Ninth Circuit held that finding was not clearly erroneous.
The Ninth Circuit also held that Dr. Ding plausibly alleged a “sexual harassment dispute” within the meaning of the EFAA. Assuming without deciding that a plaintiff must plausibly plead a covered claim, the court looked to California law and explained that a sex-based hostile work environment may constitute sexual harassment even when the challenged conduct is not sexual in nature. Because the EFAA renders a predispute arbitration agreement unenforceable with respect to an entire “case,” rather than only the covered claim, the court held that Dr. Ding could pursue all of her claims in court.
Key Takeaways
The decision confirms that an employee’s prior participation in arbitration does not necessarily foreclose a later EFAA election if a covered claim emerges as the factual record develops. Whether the employee waived EFAA rights will depend in part on what the employee knew, when the employee learned it, and whether the employee unduly delayed bringing the covered claim through intentional acts or chose to arbitrate that claim. The decision also confirms the EFAA’s potentially broad reach in the Ninth Circuit: a nonsexual but sex-based hostile work environment claim may qualify as a sexual harassment dispute under applicable state law, and one plausible covered claim may render a predispute arbitration agreement unenforceable as to the entire case, including otherwise arbitrable claims.